Anti-drawback medical valve

ABSTRACT

A gland member within a medical valve is configured to have a substantially consistent or enlarging internal volume as the valve transitions from a closed mode to an open mode. The valve has a housing forming an interior containing a flow path, and a stationary post member within the interior. The post member has a lumen that is a part of the flow path. The lumen has an opening to the interior of the housing. The valve further includes a gland member circumscribing the post member to produce a variable volume region formed at least in part between the gland member itself and the post member. The variable volume region is a part of the flow path, while the gland member occludes the post lumen opening when in the closed mode. The variable volume region has an open volume that is no less than its closed volume.

PRIORITY

This application is a continuation of U.S. patent application Ser. No.12/915,691, now U.S. Pat. No. 8,100,868, entitled “Anti-Drawback MedicalValve,” filed Oct. 29, 2010, naming Brian L. Newton, Andrew L. Cote Sr.,Charles F. Ganem, David B. Woyak, and Richard T. Boisjoly as inventors,the disclosure of which is incorporated herein, in its entirety, byreference.

U.S. patent application Ser. No. 12/915,691, in turn, claims priorityfrom U.S. patent application Ser. No. 10/895,638, now U.S. Pat. No.7,914,502, entitled “Anti-Drawback Medical Valve,” filed Jul. 21, 2004,naming Brian L. Newton, Andrew L. Cote St., Charles F. Ganem, David B.Woyak, and Richard T. Boisjoly as inventors, the disclosure of which isincorporated herein, in its entirety, by reference.

U.S. patent application Ser. No. 10/895,638, in turn, claims priorityfrom from the following provisional United States patent applications,the disclosures of which are incorporated herein, in their entireties,by reference:

-   -   Provisional U.S. patent application No. 60/491,486, filed Jul.        31, 2003, entitled, “MEDICAL VALVE WITH STATIONARY POST MEMBER,”        and naming Andrew L. Cote and Brian L. Newton as inventors,    -   Provisional U.S. patent application No. 60/516,126, filed Oct.        31, 2003, entitled, “ANTI-DRAWBACK MEDICAL VALVE,” and naming        Andrew L. Cote, Brian L. Newton, and Richard T. Boisjoly as        inventors,    -   Provisional U.S. patent application No. 60/567,639, filed May 3,        2004, entitled, “MEDICAL VALVE WITH LOBED GLAND,” and naming,        Brian L. Newton, Andrew L. Cote and David B. Woyak as inventors.

FIELD OF THE INVENTION

The invention generally relates to medical valves and, moreparticularly, the invention relates to substantially eliminating fluiddrawback in a medical valve.

BACKGROUND OF THE INVENTION

In general terms, medical valving devices often act as a sealed portthat may be repeatedly accessed to non-invasively inject fluid into (orwithdraw fluid from) a patient's vasculature. Consequently, a medicalvalve permits the patient's vasculature to be freely accessed withoutrequiring such patient's skin be repeatedly pierced by a needle.

To those ends, as a preliminary step, medical personnel insert a syringeinto a medical valve that is appropriately secured to a patient. Forexample, the valve may be coupled to a catheter having an opposite endsecured within the patient's vain. Once inserted, fluid may be freelyinjected into or withdrawn from the patient. Problems arise, however,when the syringe is withdrawn from the valve. Specifically, a backpressure (i.e., a proximally directed pressure) produced by thewithdrawing syringe undesirably can cause blood to be drawn proximallyinto the valve (e.g., via an attached catheter). In addition tocoagulating and impeding the mechanical operation of the valve, blood inthe valve (or in the catheter) also compromises its sterility.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, a gland member within amedical valve is configured to have a substantially consistent orenlarging internal volume as the valve transitions from a closed mode toan open mode. To that end, the valve has a housing forming an interiorcontaining a flow path, and a stationary post member within theinterior. The post member has a lumen that is a part of the flow path.The lumen has an opening to the interior of the housing. The valvefurther includes a gland member circumscribing the post member toproduce a variable volume region formed at least in part between thegland member itself and the post member. In addition, the variablevolume region is a part of the flow path, while the gland memberoccludes the post lumen opening when in the closed mode. The variablevolume region has an open volume (i.e., when the valve is in the openmode) that is no less than its closed volume (i.e., when the valve is inthe closed mode).

In some embodiments, the variable volume region is closed when in theclosed mode. Moreover, the gland member may move radially outwardly asthe valve transitions from the closed mode toward the open mode. In suchcase, the radial outward motion may substantially unocclude the openingto the post member lumen.

To provide an anti-drawback effect, the open volume may be greater thanor substantially equal to the closed volume. In some embodiments, thegland member has a proximal end that is substantially flush with orextends proximally of a proximal port of the housing. To provide asecond reusable seal, the proximal end of the gland may have a slit.

The gland member also may have a sealing ridge that occludes the postlumen opening when in the closed mode. Moreover, the gland member mayinclude a main wall section and a lobed portion. The main wall thicknessis greater than the lobe portion wall thickness. In fact, the lobedportion may extend radially outwardly from the main wall section. Thelobed portion may move radially outwardly as the valve moves toward theopen mode.

In various embodiments, when in the closed mode, the variable volumeregion is bounded by the post member and the gland member only. Toprovide an anti-drawback effect, the flow path illustratively has atotal volume that varies as the variable volume region varies. Forexample, the flow path total volume may increase as the volume of thevariable volume region increases.

In accordance with another aspect of the invention, a medical valve hasa housing forming an interior, and a stationary post member within theinterior. The post has a lumen for channeling fluid through theinterior. The valve also has a gland member within the interior of thehousing. The gland member forms a variable volume region that also isbounded by the post member. The gland member occludes the lumen when inthe closed mode. The variable volume region has a closed volume when inthe closed mode and an open volume when in the open mode. The openvolume is no less than the closed volume.

In accordance with another aspect of the invention, a medical valve hasa housing forming both an interior and a distal port. The valve also hasa gland member within the interior of the housing. The gland member hasa main portion and a protruding portion that together form a variablevolume region. The protruding portion protrudes radially outwardlyrelative to the main portion. Moreover, the protruding portion isdefined by a protruding wall, while the main portion is defined by amain wall portion. The protruding wall has a thickness that is less thanthe thickness of the main wall. In a manner similar to other aspects,the variable volume region has a closed volume when in the closed modeand an open volume when in the open mode. The open volume is no lessthan the closed volume to substantially prevent net fluid drawback intothe interior through the distal port. In other words, during asubstantially complete stroke of the valve from the open mode to theclosed mode, the total amount of drawn back fluid remaining in the valveshould be no greater than about zero microliters.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and advantages of the invention will be appreciated morefully from the following further description thereof with reference tothe accompanying drawings wherein:

FIG. 1 schematically shows a medical valve that may be configured inaccordance with various embodiments of the invention.

FIG. 2 schematically shows a cross-sectional view of the medical valveof FIG. 1 along line X-X in accordance with a first embodiment of theinvention.

FIG. 3 schematically shows a cross-sectional view of the medical valveof FIG. 1 along line X-X in accordance with a second embodiment of theinvention.

FIG. 4 schematically shows a cross-sectional view of the medical valveof FIG. 1 along line X-X in accordance with a third embodiment of theinvention.

FIG. 5 schematically shows a cross-sectional view of the medical valveof FIG. 1 along line X-X in accordance with a fourth embodiment of theinvention.

FIG. 6 schematically shows a perspective view of a gland member of thevalve shown in FIG. 5.

FIG. 7 schematically shows a radial cross-sectional view of the glandmember shown in FIG. 6 along line 7-7.

FIG. 8 schematically shows a longitudinal cross-sectional view of thegland member shown in FIG. 6.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In illustrative embodiments of the invention, a medical valve isconfigured to substantially eliminate fluid drawback when a nozzle orsyringe is withdrawn from it. Specifically, in one such embodiment, themedical valve produces neither a net negative nor a net positivepressure when a nozzle or syringe is withdrawn. Consequently, after thenozzle is withdrawn, the net fluid expelled from or drawn into the valveis substantially equal to zero.

To these ends, illustrative embodiments of the medical valve have afluid path with a volume that is substantially the same when it is ineither an open mode (i.e., permitting fluid flow, also referred to as“open position”) or a closed mode (i.e., preventing fluid flow, alsoreferred to as “closed position”). More specifically, a portion of thefluid path is formed from a resilient member disposed over a stationarymember. When transitioning from the closed mode toward the open mode,the resilient member both expands radially and compresseslongitudinally. This expansion and contraction is sized and configuredto ensure that the overall volume within the fluid path remainssubstantially constant as the valve transitions from the closed mode tothe open mode. In a similar manner, when retracting back to the closedmode, the resilient member operates in an opposite manner, thus furthermaintaining the fluid path volume. Details of this and relatedembodiments are discussed below.

In other embodiments, the valve produces a positive, distally directedpressure (i.e., toward its outlet) when a nozzle or syringe iswithdrawn. Such pressure should prevent fluid from being drawn into thevalve at such time. To these ends, the expandable member is sized andconfigured to expand the fluid path volume as the valve transitionstoward the open mode, and reduce the fluid path volume as the valvetransitions toward the closed mode. Details of this and relatedembodiments also are discussed below.

FIG. 1 schematically shows a medical valve 10 that is configured toreduce fluid drawback (a/k/a “back-flow” and “reflux”) when a syringe orother type of nozzle is withdrawn from it. The valve 10 includes aproximal port 12 for receiving the nozzle, a valve body 14 having aninternal valve mechanism (shown in FIGS. 2-5) that controls fluid flowthrough the valve 10, and a distal port 16 for directing fluid betweenthe valve 10 and a patient. The distal port 16 of the valve 10 may be atits location shown in FIG. 1, at a location that is orthogonal to thelongitudinal dimension of the valve 10, or at some other location. Thefluid preferably is in liquid form, such as liquid medication. Althoughmuch of the discussion herein refers to the proximal port 12 as a fluidinlet, and the distal port 16 as a fluid outlet (also referred to hereinas “outlet 16”), the proximal and distal ports 12 and 16 also may berespectively utilized as outlet and inlet ports.

The valve 10 illustratively is a swabbable, luer activated valve. Thetop surface of the valve mechanism thus should be substantially flushwith, or extend slightly outwardly from, the proximal port 12. As knownby those in the art, this arrangement permits the top surface of thevalve mechanism to be easily cleaned with a swab or other cleaningapparatus. In other embodiments, however, the valve 10 is not a swabvalve.

FIGS. 2-5 show four different embodiments of the valve 10 shown inFIG. 1. Identical reference numbers are used, however, across allfigures. For example, although they are different embodiments, eachembodiment of the valve is identified in the drawings and descriptionthat follows by reference number “10.” As a second example, eachembodiment has a gland, which is identified in all the relevant figuresby reference number “28.” Their identical reference numbering, however,should not be interpreted to imply that they are identical in structureand function. As noted below, each valve and gland (among otherelements) may operate differently to some extent. Other elements,however, may operate identically.

FIG. 2 schematically shows a cross-sectional view of one embodiment ofthe medical valve 10 (along line X-X of FIG. 1) in a closed position.More particularly, the arrangement in FIG. 1 permits the valve 10 tosubstantially eliminate fluid drawback when a syringe or other type ofnozzle is withdrawn from it. As noted above, this reduction can resultin either a positive pressure (or displacement) at the distal port 16,or a zero net pressure at the distal port 16.

Among other things, the valve 10 includes a unitary housing 18 that iscoupled with a hollow post member 20 terminating at a convex proximalportion. The interior of the housing is contoured to provide theanti-drawback effect with different types of nozzles. Specifically, theinterior is contoured to have a tapering proximal region 22 to accept anozzle, and a longitudinally adjacent, distally diverging region 24. Theproximal region 22 illustratively is contoured to accept various typesof nozzles, such as those complying with ISO/ANSI standards (e.g., lurescomplying with ISO/ANSI standards). In addition to the proximal anddiverging regions 22 and 24, the interior also has a central region 26having a significantly larger inner dimension than that of the divergingregion 24.

The valve interior contains a resilient, compressible and stretchablemember (hereinafter “gland 28”) that, in conjunction with the postmember 20, controls fluid flow through the valve 10. In illustrativeembodiments, the gland 28 is secured within the valve 10 between aninterior ledge 30 of the housing 18 and a radial surface 32 of the postmember 20. Details of the interaction of the post member 20 and thegland 28 are discussed below.

In the embodiment shown in FIG. 2, the post member 20 has a closedproximal end and a transverse channel 34 (near the proximal end of thepost member 20) that leads to an internal post member flow channel 36 (alumen through the post member). The post member flow channel 36terminates at the distal port 16. Accordingly, when open, fluid can flowinto the post member 20 via the transverse channel 34, through the postmember flow channel 36, and out the distal port 16. In alternativeembodiments, rather than use a transverse channel 34, fluid can accessthe post member flow channel 36 via an opening (not shown) in theproximal end of the post member 20. Such alternative embodiment,however, may have a single seal only (see discussion below), or beconfigured to further seal the noted opening.

The gland 28 is the only movable part within the interior of the valve10. To that end, the gland 28 has a swabbable seal section 38 having anormally closed slit 40 therethrough, and a tubular section 42 extendingfrom the seal section 38 to its base. When closed, the volume formed bythe gland 28 and the post member 20 is considered to be a closed volume.As noted below, this volume is no longer considered to be closed afterthe gland 28 is urged distally a sufficient amount so that the slit 40opens or the transverse channel 34 is not occluded. This volume isreferred to herein as the “variable volume region.” It is anticipated,however, that principles of various embodiments can be applied to othertypes of variable volume regions, such as those formed by other oradditional components. Accordingly, discussion of the noted variablevolume region is exemplary and not intended to limit all embodiments ofthe invention.

The tubular section 42 has two sub-sections; namely, 1) a normallyhollow proximal tube section 44 that, when in the closed mode, isproximal of the post member 20, and 2) a distal tube section 46 normallysubstantially circumscribing and flush against the post member 20. Dueto a radially compressive force against the post member 20 (e.g., aninterference fit), the distal tube section 46 normally occludes thetransverse channel 34, consequently acting as a second seal when in theclosed mode. In addition to the seal and tubular sections 38 and 42, thegland 28 also has an attachment section 48 secured between the postmember 20 and housing 18 (as noted above).

When closed, which is its normal state, the valve 10 uses its tworedundant seals to prevent fluid communication between the proximal anddistal ports 12 and 16. Specifically, the gland 28 prevents fluid flowthrough the transverse channel 34, while the slit 40 prevents fluid flowthrough the seal section 38. In some embodiments, the gland/transversechannel seal can withstand higher backpressures than those that the slit40 can withstand.

Insertion of a nozzle against the surface surrounding the slit 40 at theproximal end of the gland 28 opens the valve 10. Specifically, insertionof the nozzle causes the seal and tubular sections 38 and 42 of thegland 28 to both compress and move distally. Consequently, the slit 40opens and the seal section 38 both axially compresses and radiallyexpands. In a similar manner, the tubular section 42 both axiallycompresses and radially expands into/within the central region 26 of thevalve interior. At some point in the transition from the closed mode tothe open mode, the tubular section 42 no longer contacts (i.e., nolonger occludes) the transverse channel 34, consequently fully openingthe valve 10. Those in the art can configure the radially inwardpressure of the gland 28 (at the transverse channel 34) so that thevalve 10 opens after the nozzle has been inserted a pre-specifiedamount.

When open, the variable volume region is considered to have an “openvolume,” which is based upon noted axial compression and radialexpansion. In a corresponding manner, when closed, the variable volumeregion is considered to have a “closed volume.” In illustrativeembodiments, the materials and dimensions of the gland 28 are selectedto ensure that 1) both the open and closed volumes are substantiallyequal, or 2) the open volume is greater than the closed volume.

Because, in this embodiment, other regions of the fluid path aresubstantially constant, the total volume for containing fluid within thefluid path of the valve 10 changes in a manner that corresponds to thevariable volume region. Accordingly, if volume of the variable volumeregion increases, the overall volume of the fluid path increases. In asimilar manner, if the volume of the variable volume region decreases,the overall volume of the fluid path decreases.

When the open and closed volumes are substantially equal, there shouldbe no appreciable net positive or negative pressure at the distal port16 during the stroke of the nozzle as it is withdrawn (i.e., the“withdrawal stroke”). In particular, it is anticipated that during thewithdrawal stroke, the variable volume region may not maintain anexactly constant volume—it may fluctuate. In such case, at certainpoints during the withdrawal stroke, the distal port 16 may draw insmall amounts of fluid. At other points during the withdrawal stroke,however, the distal port 16 may expel small amounts of fluid. In eithercase, there may be some negligible reflux and positive expulsion offluid from the distal port 16. Various embodiments with substantiallyequal open and closed volumes, however, ensure that the net fluid in orout of the distal port 16 (i.e., the net amount of fluid during theentire withdrawal stroke) is no greater than a negligible amount. Insome embodiments, the valve 10 can be configured to ensure that thevolumes remain substantially constant at least after the transversechannel 34 is opened.

Conversely, when the open volume is greater than the closed volume, apositive pressure develops at the distal port 16 when the nozzle iswithdrawn. Accordingly, in that case, an appreciable amount of fluidwithin the valve 10 is expelled from the distal port 16. Expelling thefluid should prevent fluid from being drawn into the valve 10 at thattime.

The valve 10 may be manufactured in accordance with conventionalprocesses. For example, the housing 18 and post member 20 may beproduced from a rigid plastic, while the gland 28 may be formed from amedical grade elastomeric material, such as silicone or rubber. Othermaterials having similar properties may be used, however, as long asthey can perform the functions discussed herein.

During assembly, the gland 28 first may be inserted into the housing 18,and the post member 20 then may be secured to the housing 18. Otherassembly methods, however, first may couple the gland 28 and post member20 as a single (uncoupled) assembly. The assembly then may be insertedinto the distal end of the housing 18. Of course, other methods ofassembling the valve 10 may be used. Accordingly, discussion of specificmethods are exemplary and not intended to limit the scope of variousembodiments of the invention. In either case, the housing 18 and postmember 20 may be secured together by conventional means, such as by asnap-fit connection. Alternatively, the housing and post member 20 maybe secured together by ultrasonic welding.

FIG. 3 schematically shows a cross-sectional view of a second embodimentof the medical valve 10 shown in FIG. 1. The housing 18 includes aproximal housing portion 13 that couples with a distal housing portion15. Among other things, the distal housing portion 15 includes athreaded skirt 40, a post member 20, and a mechanism to couple with theproximal housing portion 13. In the embodiment shown in FIG. 3, a snapfit mechanism is used. As noted above, however, other conventionalcoupling methods may be used.

The gland 28 in the embodiment shown in FIG. 3 also has a plurality ofthinned sections 52 within a gland portion that fits over the postmember 20. The thinned sections 52 facilitate gland stretching over thepost member 20 while maintaining a sufficient column strength to forcethe gland 28 distally.

FIG. 4 schematically shows a cross-sectional view of a third embodimentof the medical valve 10 shown in FIG. 1 along line X-X. This embodimentof the valve 10 illustratively is produced from three components;namely, a proximal housing portion 13 having the inlet 12, a distalhousing portion 15 having the outlet 16, and a gland 28. The two housingportions 18 and 20, which are formed from a hard plastic material, aresnap-fit or welded together to form the valve body/housing 14.

In a manner similar to other embodiments, the housing portions 18 and 20form a specially shaped interior. Specifically, the interior has atapering proximal region 22 to accept a nozzle, a longitudinallyadjacent, distally diverging region 24, and a larger central region 26.These regions illustratively are similar to those corresponding regionsdiscussed above with reference to FIG. 2.

The distal housing portion 15 also has a stationary, hollow post member20 that terminates at a convex proximal portion. A hoop groove(hereinafter “groove 54”) having two through-holes illustratively iscircumferentially formed around the outer surface of the post member 20.The through holes effectively form the transverse channel 34 and thus,also are identified by reference number 34. The two through-holes 34form ports to a flow channel 36 extending through the post member 20.

In accordance with illustrative embodiments of the invention, the valve10 also has a resilient, compressible, and stretchable gland 28positioned about the post member 20 and secured between the proximalhousing portion 13 and distal housing portion 15. More specifically, thegland 28 illustratively is positioned over the post member 20 tonormally occlude fluid flow through the valve 10 when in the closedmode. To that end, the gland 28 has a sealing ridge 58 extendingradially inwardly from its interior wall. To ensure a close fit with thepost member 20, the sealing ridge 58 normally is in registry with thegroove 54 when in the closed mode. Accordingly, the groove 54 andsealing ridge 58 are formed to be complimentarily shaped to close thetwo through-holes 34 when mated.

To ensure a secure fit between the sealing ridge 58 and groove 54, thegland 28 is secured within the housing interior in a manner thatnormally applies a radially inward pre-load force. To that end, thesealing ridge 58 is a part of a sealing ring 60 that normally iscompressibly secured between the proximal and distal housing portions 13and 15. Moreover, the sealing ring 60 normally is under a radiallycompressive force that ensures a secure fit within the groove 54, thusoccluding fluid flow through the two through-holes 34. The amount ofradial force can be selected during design to ensure that this portionof the valve 10 effectively forms a high pressure seal that canwithstand relatively large back pressures (e.g., those higher pressuresthat may occur during anticipated use, such as pressures up to orgreater than about 60 p.s.i.). Other embodiments, however, eliminate thepre-load.

In illustrative embodiments, the gland 28 also has a seal section 38that normally is flush with, or extends slightly above, the inlet 12 ofthe valve 10. Accordingly, in a manner similar to other embodiments, thevalve 10 is considered to be a “swabbable” luer activated valve. Theseal section 38 is configured to act as a low pressure seal. Morespecifically, the seal section 38 has a normally closed slit 40. Wheninserted into the inlet 12, a nozzle or syringe deforms the seal section38, consequently opening the low pressure seal.

In various embodiments discussed herein, the slit 40 is normally closedwhen the gland 28 is not mounted within the housing 14. No radial forcethus is required (by the housing 14) to close the slit 40. In fact, insome embodiments, the outer dimension of the seal section 38 is smallerthan the inner dimension of the inlet 12. In alternative embodiments,however, the inner dimension of the inlet 12 is smaller than the outerdimension of the seal section 38 of the gland 28. Consequently, in suchembodiments, the housing 14 squeezes the seal section 38, therebyforcing the slit 40 closed. Those skilled in the art may shape the inlet12 to ensure closure of the slit 40 when the valve 10 is in the closedmode.

As noted above, it is anticipated that the high pressure seal canwithstand relatively high pressures. Accordingly, due to the performanceof the high pressure seal, it is not necessary for the low pressure seal(i.e., the slit 40 through the seal section 38) to resist large backpressures. In some embodiments, however, the low pressure seal also maybe formed to resist relatively high back pressures.

In addition to the seal section 38 and sealing ring 60, the gland 28also has a main section 62 extending distally from the somewhat looselydefined distal end of the seal section 38 to a proximally facinginterior surface of the housing 14. In fact, the sealing ring 60 extendsradially outwardly from the main section 62 of the gland 28. The valve10 thus has a fluid path with two portions; namely, a dynamic portion 64primarily formed by the gland 28 (i.e., the variable volume region), anda static portion 66 partially formed by the post member 20. Morespecifically, the dynamic portion 64 generally includes the regionformed between the gland 28 and the post member 20. This portion 50 thusextends from the slit 40, through the gland main section 62 to the twothrough-holes 34 in the post member 20, and to the base of the housinginterior. The static portion 66 extends from the interior of the postmember 20 to the outlet 16. In other words, the lumen through the postmember 20 forms the static portion 66.

In a manner similar to other embodiments discussed above, the mainsection 62 of the gland 28 is both longitudinally compressible andradially expandable to vary the volume of the dynamic portion 64 of thefluid path. In particular, when a nozzle (e.g., a luer) is inserted intothe inlet 12, the seal section 38 of the gland 28 collapses to deformthe slit 40 (as noted above). At the same time, however, the mainsection 62 of the gland 28 should both longitudinally compress andradially expand. When a sufficient amount of radial force is applied tothe gland main section 62, the sealing ridge 58 moves radially outwardlyfrom its registration contact with the groove 54. In other words, whenthe radial force at the sealing ring 60 is equal to or slightly greaterthan the pre-loaded, radially inward compressive force applied by thesealing ring 60, the sealing ridge 58 moves radially outwardly fromoccluding contact with the through-holes 34. Consequently, the twothrough-holes 34 open, thus permitting fluid flow through the valve 10.

As noted above, in some embodiments, the compressive and expansiveoperation of the gland 28 (in response to an inserted nozzle) causes theshape of the dynamic portion 64 of the flow path to change. Although itsshape changes, neutral embodiments are configured to ensure that the netvolume of the dynamic portion 64 remains substantially constant as thevalve 10 transitions between open and closed modes. To that end, theamount of clearance between the interior wall of the proximal housingportion 13 is selected as a function of the anticipated compressiveproperties of the gland 28. As a result, the outlet 16 should notdevelop a non-negligible positive or negative pressure and thus,eliminate non-negligible fluid drawback.

In alternative embodiments, although the interior volume of the dynamicportion 64 of the fluid path is substantially the same at both the openand closed positions, it may fluctuate as the valve 10 transitionsbetween such positions. In yet other embodiments, the interior volume isgreater when the valve 10 is in the open position than when it is in theclosed position. In such case, the valve 10 produces a distally directedpositive pressure through the outlet 16 when closing. Accordingly, insuch embodiment, fluid is forced out through the outlet 16 as the valve10 moves toward the closed position.

In some embodiments, the interior volume of the gland 28 depends uponthe depth of penetration of the nozzle. Specifically, the internalvolume may remain substantially constant to a specified depth within thevalve 10. Further distally directed insertion, however, may cause theinternal gland volume to increase. In yet other embodiments, dependingupon the longitudinal depth of the nozzle, the interior volume of thevalve 10 may have both specified amounts of fluid drawback and distallydirected fluid pressure at different times during its travel betweenopen and closed positions. Stops (not shown) may be inserted in theinterior of the housing 14 to limit the insertion depth of a nozzle.

The gland 28 should operate as intended by properly selecting thevarious gland and housing design parameters. For example, among otherthings, the gland durometer and flexibility (modulus) are selected tocoordinate with the appropriate gland and housing dimensions, thusproviding the desired end performance. Iterative testing processes alsocan be used to fine tune gland performance. Computer simulation toolscan further enhance the testing process. For example, the performance ofthe gland 28 can be modeled by finite element software (“FEA” software),such as ABAQUS EXPLICIT FEA software, distributed by Abaqus East LLC ofWarwick, R.I.

In use, it is anticipated that the neutral design (i.e., the designwhere the gland 28 maintains substantially the same volume as ittransitions between positions) may have some error factor that causesnegligible amounts of fluid drawback or positive push through its outlet16. Such negligible amounts, however, only should have negligible impacton the general goals of a neutral design.

Moreover, some embodiments may coat the interior of the housing 14 witha conventionally available anti-bacterial coating to further protect itssterility. Alternatively, conventional anti-bacterial material can beincorporated directly into the housing or gland materials.

Some embodiments of the invention have more than the three notedcomponents (i.e., proximal housing portion 13, distal housing portion 15with integrated post member 20, and gland 28). For example, the valve 10also may include a gland securing member 80 within its interior tofurther secure the sealing ring 60 within its interior. Of course,illustrative embodiments integrate such member into the distal housingportion 15.

Accordingly, in illustrative embodiments, radial inward stress (alsoreferred to in the art as “hoop stress”) applied to the sealing ridge 58normally occludes fluid flow through the valve 10. Moreover, the volumeof the dynamic portion 64 of the fluid path substantially eliminatesfluid drawback through the valve 10.

FIG. 5 schematically shows a cross-sectional view of a fourth embodimentof the medical valve 10 (along line X-X of FIG. 1) in a closed position.More particularly, FIG. 5 schematically shows a cross-sectional view ofan embodiment of the medical valve 10 shown in FIG. 1, which also isconfigured to substantially eliminate fluid drawback during a withdrawalstroke. As noted above, this reduction can result in either a positivepressure at the distal port 16, or a zero net pressure at the distalport 16.

Among other things, the valve 10 includes a housing 14 containing aresilient, compressible, and stretchable gland 28. More specifically,the housing 18 includes a proximal housing portion 13 coupled with adistal housing portion 15 incorporating a post member 20. Anyconventional coupling means may be used, such as ultrasonic welding orconventional snap-fit techniques. The gland 28 and post member 20cooperate to control fluid flow through the valve 10. In illustrativeembodiments, the gland 28 is secured within the valve 10 between the twohousing portions. Details of the interaction of the post member 20 andthe gland 28 are discussed below.

In the embodiment shown in FIG. 5, the post member 20 has a closed,convex proximal end and a transverse channel 34 that leads to aninternal post member flow channel 36. In a manner similar to otherembodiments, the post member flow channel 36 merges into a distal flowchannel 68 that terminates at the distal port 16. Accordingly, the gland28 normally is pre-loaded to occlude the transverse channel 34, thuspreventing fluid flow. Application of a downward pressure (e.g., by anozzle) causes the gland 28 to separate from the transverse channel 34,consequently opening the valve 10. When open, fluid can flow into thepost member 20 via 1) the transverse channel 34, 2) through the postmember flow channel 36, 3) through the distal flow channel 68, and 4)out the distal port 16.

In a manner similar to other embodiments, the gland 28 is the onlymovable part within the interior of the valve 10. To that end, the gland28 has a swabbable seal section 38 having a normally closed slit 40therethrough, a main section 62 extending from the seal section 38 toits base, and a radial attachment section 48 that secures the gland 28within the valve 10. In accordance with illustrative embodiments of theinvention, the main section 62 has a relatively thick main wall 70 witha plurality of radially protruding lobes 72. The lobes 72 preferablyhave thinner walls than those of the main section 62 (i.e., the mainwalls 70). Consequently, the lobes 72 should expand with less resistancethan the main wall 70. Accordingly, the lobes 72 should radially expanda greater distance than that of the main section walls 70. Details ofthis portion of the gland 28 are discussed in greater detail below.

The main section 62 of the gland 28 also has an occluding portion 74that normally occludes the transverse channel 34, consequently acting asthe noted second seal when in the closed mode. The valve 10 thus has twoseal areas; namely, the seal at the transverse channel 34 and the slit40 in the seal section 38. Accordingly, when closed, which is its normalstate, the valve mechanism uses its two redundant seals to prevent fluidcommunication between the proximal and distal ports 12 and 16.Specifically, when closed, the gland 28 prevents fluid flow through thetransverse channel 34, while the slit 40 prevents fluid flow through theseal section 38.

In some embodiments, the gland/transverse channel seal can withstandhigher backpressures than those that the slit 40 can withstand. To thatend, the occluding portion 74 may be formed to have about a 0.010 inchinterference fit against the post member 20. In addition to enabling thevalve 10 to withstand higher backpressures, the fit of the occludingportion 74 against the post member 20 also should be selected to openthe transverse channel 34 at an appropriate point in the opening strokeof the valve 10.

FIG. 6 schematically shows a perspective view of the gland 28 shown inFIG. 2. As shown, the gland 28 has four lobes 72 extending from the mainsection 62. Each of the lobes 72 is radially spaced about ninety degreesfrom two other lobes 72 along the main section 62. In alternativeembodiments, rather than being spaced around the circumference of thegland 28, the lobes 72 may be longitudinally spaced. In other words, thegland 28 may have two or more lobes 72 spaced along its longerdimension. Moreover, the attachment section 48 has a circumferentialridge 76 and flange 78 to further secure the gland 28 within the valve10.

FIG. 7 shows the relative wall thicknesses of the lobes 72 and the mainwall 70, while FIG. 8 shows the lobes 72 from the gland interior. Asshown, the main walls are several times thicker than the lobe walls 70.For example, the lobe wall may be about 0.010 inches thick, while themain walls 70 may be about 0.053 inches thick. These relativethicknesses should provide a sufficient column strength to the gland 28to minimize its likelihood that it will collapse when compressed.Instead of collapsing entirely, the lobes 72 should expand radially tosome extent, while the main wall 70 substantially maintains its radialposition (subject to some expansion or deformation that does notadversely affect valve operation). In some embodiments, however, themain wall 70 also expands radially as the lobes 72 expand.

Insertion of a nozzle against the slit 40 at the proximal end of thegland 28 causes the seal section 38 to both compress and move distally.Consequently, the slit 40 opens and the seal section 38 both axiallycompresses and radially expands. In a similar manner, the main section62 both axially compresses and radially expands. Specifically, the lobes72 radially expand, while the main walls 70 radially expand much lesssignificantly.

It is anticipated, however, that the lobes 72 attain a maximum volumebefore the nozzle is fully inserted into the valve 10. After that point,the lobes 72 axially compress to some extent, which may produce somepositive pressure from the interior of the lobes 72. In a correspondingmanner, when withdrawing the nozzle from full insertion, it isanticipated that the lobes 72 actually may expand to some extent beforecontracting. Accordingly, during nozzle withdrawal, some negativepressure may draw fluid into the valve 10. Despite these imperfections,it is anticipated that the lobes 72 ultimately will produce the desiredanti-drawback effect by the time the nozzle is fully withdrawn from thevalve 10. The negative impact of the noted lobe compression thus isexpected to have a negligible effect on the overall operation of thevalve 10.

At some point in the transition from the closed mode to the open mode,the occluding portion 74 of the gland 28 no longer contacts (i.e., nolonger occludes) the transverse channel 34, consequently fully openingthe valve 10. When open, the volume of the variable volume region isbased upon the noted gland axial compression and radial expansion. Inillustrative embodiments, the materials and dimensions of the gland 28are selected to ensure that 1) both the open and closed volumes aresubstantially equal, or 2) the open volume is greater than the closedvolume.

When the volumes are substantially equal, there should be no appreciablepositive or negative net pressure at the distal port 16 when the nozzleis withdrawn. Accordingly, in such case, only negligible amounts offluid drawback or distally directed pressure, if any, should occur.Conversely, when the open volume is greater than the closed volume, anet positive pressure develops at the distal port 16 when the nozzle iswithdrawn. Accordingly, in that case, an appreciable amount of fluidwithin the valve 10 is expelled from the distal port 16. Expelling thefluid should prevent fluid from being drawn into the valve 10 at thattime.

The valve 10 may be manufactured in accordance with conventionalprocesses. In a manner similar to other embodiments, the housing 14 andpost member 20 may be produced from a rigid plastic, while the gland 28may be formed from a medical grade elastomeric material, such assilicone or rubber. Moreover, the post member 20 may be a separate pieceinserted into the outlet portion of the housing 14, as shown in FIG. 5,or it may be integral with the housing 14. In the latter case, the postmember 20 is considered to be a part of the housing 14. This alsoapplies to other embodiments.

Although the above discussion discloses various exemplary embodiments ofthe invention, it should be apparent that those skilled in the art canmake various modifications that will achieve some of the advantages ofthe invention without departing from the true scope of the invention.

What is claimed is:
 1. A medical valve having an open mode that permitsfluid flow through an internal flow path, the medical valve also havinga closed mode that prevents fluid flow through the internal flow path,the medical valve comprising: a housing forming an interior containingthe flow path; a post member within the interior, the post member havinga lumen that is a part of the flow path and a solid wall surrounding anddefining the lumen, the lumen having an opening to the interior of thehousing; and a gland member circumscribing the post member to form avariable volume region, the variable volume region being formed at leastin part between the gland member and the post member, the variablevolume region being a part of the flow path, the gland member having aninward projection extending into and obstructing the post lumen openingwhen in the closed mode, at least a portion of the post member lumenextending into the gland member, the variable volume region having aclosed volume when in the closed mode, the variable volume region havingan open volume when in the open mode, the open volume being no less thanthe closed volume.
 2. A medical valve according to claim 1, wherein theinward projection is a sealing ridge, the sealing ridge extending to thepost lumen opening.
 3. A medical valve according to claim 1, wherein theinward projection and the post lumen opening have complimentary shapes.4. A medical valve according to claim 1, wherein the variable volumeregion is closed when in the closed mode.
 5. A medical valve accordingto claim 1, wherein the housing has a proximal port, the gland memberhaving a proximal end that is substantially flush with or extendsproximally of the proximal port.
 6. A medical valve according to claim1, wherein the inward projection moves out of the post member lumenopening as the valve transitions from the closed mode toward the openmode, thereby unobstructing the post lumen opening.
 7. A medical valveaccording to claim 1, wherein the open volume is greater than the closedvolume.
 8. A medical valve according to claim 1, wherein the open volumeis substantially equal to the closed volume.